A7♭9 — A dominant seventh flat ninth chord
A dominant seventh chord with the ninth flattened. The flat ninth sits a semitone above the root in the octave above, and the chord resolves down a fifth.
- 1 = A
- 3 = C#
- 5 = E
- b7 = G
- b9 = Bb
- Symbol
- A7♭9
- Root
- A
- Quality
- Dominant seventh flat ninth
- Family
- altered
- Notes
- A C# E G Bb
- Degree formula
1 3 5 b7 b9- Semitones from the root
0 1 4 7 10- Distinct pitch classes
- 5
- Interval structure
- Stacked from the root: 4 semitones, 3 semitones, 3 semitones, 3 semitones
- Notation
- Written 7♭9. The dominant of a minor key, because the flat ninth belongs to the harmonic minor scale of the target.
- Key
- A · A major / F# minor key signature
Fingering charts
The library holds 5 fingerings of this chord and all of them are shown, in the library’s own order. Several fingerings of one chord is normal: the same notes can be stopped at different positions and on different strings.
Formula
The chord tones in order from the root, with the interval each one forms above it.
| Degree | Note | Semitones | Interval from the root |
|---|---|---|---|
| 1 | A | 0 | Perfect unison |
| 3 | C# | 4 | Major third |
| 5 | E | 7 | Perfect fifth |
| b7 | G | 10 | Minor seventh |
| b9 | Bb | 1 | Minor second |
Inversions
An inversion is the same set of notes with a different one in the bass. The last column gives the distance of each note above the bass note, in semitones.
| Inversion | Bass note | Degree in the bass | Notes above the bass | Semitones above the bass |
|---|---|---|---|---|
| root position | A | 1 | A – C# – E – G – Bb | 0 4 7 10 1 |
| first inversion | C# | 3 | C# – E – G – Bb – A | 0 3 6 9 8 |
| second inversion | E | 5 | E – G – Bb – A – C# | 0 3 6 5 9 |
| third inversion | G | b7 | G – Bb – A – C# – E | 0 3 2 6 9 |
| fourth inversion | Bb | b9 | Bb – A – C# – E – G | 0 11 3 6 9 |
Playable voicings
These shapes were found by searching the fretboard of a standard-tuned guitar (E A D G B E) rather than copied from a chord book. The search allows every string to sound or to be muted, rejects any shape with a muted string between two sounding strings, rejects any shape whose fretted notes span more than four frets (a five-fret window), requires every chord tone to be present, and then sorts what remains with root-position shapes first and the most compact, lowest shapes next. The shapes shown are the first six of that ordering; other orderings are possible at the same frets.
| # | Shape (low string first) | Notes | Degrees | Bass | Span (frets) | Sounding strings |
|---|---|---|---|---|---|---|
| 1 | 5-4-5-3-5-3 | A C# G A# E G | 1 3 b7 b9 5 b7 | A | 2 | 6 |
| 2 | 5-4-5-3-5-5 | A C# G A# E A | 1 3 b7 b9 5 1 | A | 2 | 6 |
| 3 | 5-4-5-6-5-6 | A C# G C# E A# | 1 3 b7 3 5 b9 | A | 2 | 6 |
| 4 | 5-7-5-6-5-6 | A E G C# E A# | 1 5 b7 3 5 b9 | A | 2 | 6 |
| 5 | 5-4-2-3-2-3 | A C# E A# C# G | 1 3 5 b9 3 b7 | A | 3 | 6 |
| 6 | 5-4-2-3-5-3 | A C# E A# E G | 1 3 5 b9 5 b7 | A | 3 | 6 |
Shape numbers run from the lowest string to the highest, so the left-hand number is the sixth string (low E) in standard tuning. Multiple shapes are listed because a chord can be voiced several ways, and because a lower position is not always the better sounding one.
Related chords and scales
- KeyEverything in A
- ScaleA diminished (half-whole)
- ChordA7
- ChordA
Related